Spark Plug Inspection/Replacement: Notes

Remove the spark plugs, and note which cylinder each one came from.
Inspect the electrodes and ceramic insulator.
- Burned or worn electrodes may be caused by:
  - Advanced ignition timing
  - Loose spark plug
  - Insufficient cooling
- Fouled plug may be caused by:
  - Retarded ignition timing
  - Oil in combustion chamber
  - Incorrect spark plug gap
  - Excessive idling/low speed running
  - Clogged air cleaner element
  - Deteriorated ignition coil
Fig 1: Inspecting Electrodes And Ceramic Insulator
Courtesy of AMERICAN HONDA MOTOR CO., INC.
If the spark plug electrode is dirty or contaminated, clean the electrode with a plug cleaner.
NOTE:
- Do not use a wire brush or scrape the iridium electrode since this will damage the electrode.
- Use a chemical cleaner such as Carb Spray to clean contamination on the electrode.
- When using a sand blaster spark plug cleaner, do not clean for more than 20 seconds to avoid damaging the electrode.
Do not adjust the gap (A) on iridium tip plugs; replace the spark plug if the gap is out of specification.
Electrode Gap

Standard (New): 1.0-1.1 mm (0.039-0.043 in.)

Fig 2: Identifying Spark Plug Gap
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Replace the plug at the specified interval, or if the center electrode is rounded (A). Use only the spark plug as listed.
Spark Plug:

ILZFR5A11 (NGK)

Fig 3: Identifying Spark Plug Center Electrode
Courtesy of AMERICAN HONDA MOTOR CO., INC.

If spark plugs need to be replaced, select the spark plugs according to the designation on the cylinder head and the table shown.

Fig 4: Identifying Cylinder Head Marks

Courtesy of AMERICAN HONDA MOTOR CO., INC.

MARK SPECIFICATIONS

Apply a small amount of anti-seize compound to the plug threads, and screw the plugs into the cylinder head, finger-tight. Torque them to 23 N.m (2.3 kgf.m, 17 lbf.ft).
NOTE: If a spark plug is to be reused, use it in the cylinder where the plug was originally located.